1. Field of the Invention
The present invention relates to a probe card used for measurement of electrical properties of a semiconductor integrated circuit element and the like.
2. Description of the Related Art
In general, in the step of manufacturing a semiconductor integrated circuit element and the like, there is a wafer test step for testing whether individual chips on a wafer are good or defective. In this wafer test, usually, first, a probe card is attached to a device called a prober. After bringing a probe of the probe card into contact with a predetermined pad (electrode) on the chip of the wafer, a given or more pressure is applied (referred to as overdrive action), thereby to perform the test.
In recent years, to shorten the test time, it has become an important challenge to increase the number of simultaneous measurements of the probe card. In the cantilever system card which is a conventional known art, condition that limit the number of needle pricking are strict, and the number of simultaneous measurements is limited. Hence, the research and development by adopting a vertical needle system probe card and a photolithography probe card has been prevailing (for example, Japanese Patent Application Laid-Open No. 2006-98064).
A side cross-sectional view of a conventional ordinary vertical needle system probe card is shown in FIG. 1.
A conventional vertical needle system probe card 100 comprises a substrate 110 having-through-holes 101 formed therein, a needle position support base 104 having guide holes 104a formed therein, and probes 102. Substrate 110 and needle position support base 104 are sandwiched by reinforcing plates 103a and 103b, and are fixed by bolt 106. Reinforcing plates 103a and 103b are for enhancing the rigidity of the substrate 110 against a needle load. Substrate 110 is prevented from bending upon receipt of the needle load through overdrive action by reinforcing plates 103a and 103b. The root of probe 102 is fixed at the upper part of through-hole 101 of substrate 110 by solder 105. Probe 102 is put into a bent state inside through-hole 101, and can absorb a pushing amount by overdrive action. Further, the interior of substrate 110 is provided with wiring for introducing electrical signals from an electrical testing device (tester), and the through-holes 101 are connected to this wiring.
Next, an electrical test (probing) by the probe card of the conventional embodiment will be described.
First, an unillustrated stage mounted with a semiconductor circuit element 200 is raised, and the top end portion of the probes 102 and pads 201 of the semiconductor circuit element 200 are brought into contact. Then, overdrive action is applied to the stage in the contact direction to break an oxide film on the pad surface, the stage is applied with overdrive action toward the contact direction. Electrical signals from the electrical testing device (tester) are transferred to the pads 201 of semiconductor circuit element 200 through the wiring, through-holes 9 and probes 102 inside substrate 110, so that the electrical test of the semiconductor circuit element 200 is conducted. After that, the stage comes down, and performs a step and repeat up to the position of a semiconductor circuit element 200 in which the next test is performed, and is raised again to perform the test of the next semiconductor element 200. By repeating these operations, it can be determined whether all semiconductor circuit elements 200 are working properly.
However, when the substrate of the probe card is bent by the needle load when performing the electrical test (probing) due to the increase of the number of needles to be pricked accompanied with an increase of the number of simultaneous measurements, a reliable electrical test result cannot be obtained. Hence, heretofore, in spite of the fact that the rigidity of the substrate is enhanced by the reinforcing plates, more reliability needs to be secured.